You should make sure your artwork is aligned with the points/pixels of the Artboard; and you should work in whole points/pixels; your sizes are 521.509 x 255.002. The sizes of the Clipping Mask and the image are yet different, irregular measuers.
If you select everything except for the outer frame, the size is 543.5 x 255.004 which explains the 544 x 256.
I am still with 10 so type is reinterpreted; some frame or the border of the type is extending past the rest.
Select the different parts, delete what is not needed, adjust sizes to fit the desired overall size, and make sure the outermost edges of the outermost parts, including strokes as you are aware of, fit into an integer values rectangle of the Artboard/Workspace.
As Jacob said, adjust your stuff. Since you seem to design this for web or video, make sure to use pixel preview to place and size your stuff within full pixel increments.
Other options are to use the outer Reference Points in the Transform palette and to tick Use Preview Bounds in the preferences while you are at it.